This invention relates to a signaling system providing a selected character display in response to the selective actuation of an input and is particularly desirable for use in an elevator system in which a remotely located position indicator selectively displays a position indicating character in response to the operation of a position sensor sensing the relative movement of an elevator car with respect to a plurality of floors.
Elevator car position displays have long been utilized to visually convey the relative position of an elevator car with respect to the floors or landings of which it serves to passengers riding within the car and in some cases to prospective passengers located at various floors or landings or to maintenance or supervisory personnel located at a central control station. Some position indicators located at floors or landings have responded to indicate the presence of the car at that particular landing only. Other types of position indicators utilized at landings and possibly within cars have included mechanical, semi-circular indicators having rotating arrow pointers to indicate the car's location by pointing to one of a plurality of semi-circular positioned numbers corresponding to the number of floors in the building.
Other elevator car position displays have selectively energized one of a predetermined number of lamps each corresponding to a particular floor and mounted to illuminate a numerical character displayed on a transparent mask or as jewels in a face plate and corresponding to such floor, such as illustrated in the U.S. Pat. No. 2,741,755 issued on Apr. 10, 1956. The use of such an indicator for an exceedingly tall building structure would necessarily require a quite large and cumbersome display panel.
Other types of elevator car position indicators have utilized a window through which position indicia located upon a rotating drum are successively exposed through operation of a notching or stepping motor, such as illustrated in the U.S. Pat. No. 3,103,645 issued on Sept. 10, 1963.
The utilization of incandescent or gaseous discharge lamps frequently pose a problem due to burn outs through repetitive use thereby requiring the elevator car to be put out of service for replacement of such lamps.
Light emitting diodes (LEDs) have been utilized within elevator position displays and arranged into display groups for selective energization to form certain alpha numeric characters having extreme brilliance and long operating life. One system has proposed the utilization of one or more of the standard seven segment or figure eight segmented displays which are capable of providing the numerals 0 through 9 inclusive, and several alpha characters such as L for the lobby designation, P for the pool or penthouse designation, or C for the cafeteria designation, for example. Such an elevator position indicating system has further proposed another seven segment display utilizing light emitting diodes only with the figure eight configuration tilted approximately 45.degree. so that selected pairs of segments can be selectively energized to formulate up and down direction arrows. While such proposed systems have desirably been utilized to display certain alpha numeric characters, they have been unable to desirably display certain alpha characters which have been customarily utilized with past elevator systems for designating the basement and the mezzanine, namely the letters B and M.
One proposed conventional seven segment light emitting diode display utilizes a five-deck make-before-break stepper switch possible utilized with a signal converter to supply a coded signal through a traveling cable leading to an elevator car or through a fixed cable leading to a landing. Such cables in the proposed system may consist of five control leads, one common lead and one blank lead (such as for indicating a not-in-service condition) for supplying control signals to the position display unit to control the energization of two distinct character LED displays. Such coupling cables in turn, have been connected to the two conventional seven segment LED displays through a diode coupling matrix utilized to selectively energize the LED segments. Such an arrangement, however, is extremely susceptible to transient conditions such as possibly occurring in response to the operation of the elevator car door when the car stops at a particular landing. Such transient or noise signals can cause a malfunction within the position LED display and can destroy or damage the diode matrix circuit or other associated LED driving circuitry to thereby render the entire position indicating system inoperative and in need of repair.
Other types of position indicating systems for elevators have employed a single array or group consisting of rows and columns of light emitting diodes with each diode selectively controlled by a discrete diode matrix for selectively energizing each diode independently of other surrounding diodes. Some such systems have employed an oscillatory scanning sequence which sequentially scans all pre-programmed alpha numeric characters while control signals supplied through the coupling cable stop the scan at the appropriate desired character to illuminate certain LEDs on an individual basis to formulate the required display. While such systems employing arrays of individually energized LEDs have been operably utilized, some have not produced the desired highly distinctive character features due to a failure to provide a proper illuminating correlation with adjacent illuminated diodes for certain characters.